Chemistry - Complete Pblock- Question with Solution | TestHub

In ${\mathrm{BF}}_3$, there is back bonding in between fluorine and boron due to presence of $p$-orbital in boron. < smiles> < /smiles> back bonding imparts double bond characteristics. As ${\mathrm{BF}}_3$ forms adduct the back bonding is no longer present and thus double bond characteristic disappears. Hence, bond becomes a bit longer than earlier $(1.30\mathring{A})$.